Catheter balloon systems and methods

ABSTRACT

An apparatus for treatment of a bifurcation of a body lumen, the bifurcation having a main vessel and a branch vessel, the apparatus includes a bifurcated balloon with a first branch portion and a second branch portion, the second branch portion including an inflatable portion adapted to extend toward the branch vessel, the bifurcated balloon also having a proximal shaft portion and a distal shaft portion connected to the inflatable portion of the second branch portion, and wherein the first branch portion and the second branch portion each have a longitudinal axis, the axis of the first branch portion being substantially parallel to the longitudinal axis of the second branch portion.

CROSS REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. § 1.19(e), this application claims the benefit ofpriority of U.S. Provisional Application No. 60/488,006 filed Jul. 18,2003; U.S. Provisional Application No. 60/518,870 filed Nov. 12, 2003;U.S. Provisional Application No. 60/547,778 filed Feb. 27, 2004; andU.S. Provisional Application No. 60/548,868 filed Mar. 2, 2004. Thecomplete disclosures of the above-referenced applications areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to the field of medical balloon cathetersand, more particularly, to systems for delivering a stent at or near abifurcation of a body lumen.

BACKGROUND OF THE INVENTION

Balloon catheters, with or without stents, are used to treat strictures,stenoses, or narrowings in various parts of the human body. Devices ofnumerous designs have been utilized for angioplasty, stents and graftsor combination stent/grafts. Varied catheter designs have been developedfor the dilatation of stenoses and to deliver prostheses to treatmentsites within the body lumen.

Illustrative procedures involving balloon catheters include percutaneoustransluminal angioplasy (PTA) and percutaneous transluminal coronaryangioplasty (PTCA), which may be used to reduce arterial build-up suchas caused by the accumulation of atherosclerotic plaque. Theseprocedures involve passing a balloon catheter over a guidewire to astenosis with the aid of a guide catheter. The guidewire extends from aremote incision to the site of the stenosis, and typically across thelesion. The balloon catheter is passed over the guidewire, andultimately positioned across the lesion.

Once the balloon catheter is positioned appropriately across the lesion,(e.g., under fluoroscopic guidance), the balloon is inflated, whichbreaks the plaque of the stenosis and causes the arterial cross sectionto increase. Then the balloon is deflated and withdrawn over theguidewire into the guide catheter, and from the body of the patient.

In many cases, a stent or other prosthesis must be implanted to providesupport for the artery. When such a device is to be implanted, a ballooncatheter which carries a stent on its balloon is deployed at the site ofthe stenosis. The balloon and accompanying prosthesis are positioned atthe location of the stenosis, and the balloon is inflated tocircumferentially expand and thereby implant the prosthesis. Thereafter,the balloon is deflated and the catheter and the guidewire are withdrawnfrom the patient.

Administering PTCA and/or implanting a stent at a bifurcation in a bodylumen poses further challenges for the effective treatment of stenosesin the lumen. For example, dilating a main vessel at a bifurcation maycause narrowing of the adjacent branch vessel. In response to such achallenge, attempts to simultaneously dilate both branches of thebifurcated vessel have been pursued. These attempts include deployingmore than one balloon, more than one prosthesis, a bifurcatedprosthesis, or some combination of the foregoing. However,simultaneously deploying multiple and/or bifurcated balloons with orwithout endoluminal prostheses, hereinafter individually andcollectively referred to as a bifurcated assembly, requires accurateplacement of the assembly. Deploying multiple stents requirespositioning a main body within the main vessel adjacent the bifurcation,and then attempting to position another stent separately into the branchvessel of the body lumen. Alternatives to that include deploying adedicated bifurcated stent including a tubular body or trunk and twotubular legs extending from the trunk. Examples of bifurcated stents areshown in U.S. Pat. No. 5,723,004 to Dereume et al., U.S. Pat. No.4,994,071 to MacGregor, and U.S. Pat. No. 5,755,734 to Richter et al.

Additional bifurcation stent delivery systems that provide improvedreliable treatment at bifurcations are disclosed, for example, in U.S.Pat. No. 6,325,826 to Vardi et al. and U.S. Pat. No. 6,210,429 to Vardiet al. The contents of these aforementioned patents are incorporatedherein by reference.

A need still exists for further improved devices and techniques fortreating a bifurcated body lumen. For example, a need further exists foradditional stent delivery systems that can be used with stents having abranch access side hole and/or an extendible branch portion.

SUMMARY OF THE INVENTION

The present invention is directed to devices and techniques for treatinga bifurcated body lumen including systems for delivering an endoluminalprosthesis at or near a bifurcation of a body lumen. Systems, devicesand techniques are disclosed comprising balloon catheters configured tosuccessfully and reliably deploy stents at a bifurcation in a bodylumen. Additionally, the balloon catheters can be employed as balloonangioplasty catheters to treat occlusions in blood vessels such as forinstance in percutaneous transluminal coronary angioplasty (PTCA)procedures.

According to one aspect, the present invention provides an apparatus fortreatment of a bifurcation of a body lumen, the bifurcation comprising amain vessel and a branch vessel, the apparatus comprising: a bifurcatedballoon comprising a first branch portion and a second branch portion;the second branch portion comprising an inflatable portion adapted toextend toward the branch vessel, the balloon further comprising aproximal shaft portion and a distal shaft portion connected to theinflatable portion.

According to another aspect, the present invention provides a system fortreatment of a bifurcated body lumen, the system comprising: a catheterfor insertion into said body lumen, the catheter having a bifurcateddistal end comprising first and second branches; and a bifurcatedballoon positioned on one of said first and second branches; the balloonhaving a first balloon branch portion and a second balloon branchportion, the first balloon branch portion including a first inflatableportion and the second balloon branch portion including a secondinflatable portion, and wherein the first inflatable portion has agenerally cylindrical shape when inflated and the second inflatableportion has a generally offset bulbous shape when inflated.

According to yet another aspect, the present invention provides a methodof treating a bifurcation of a body lumen, the bifurcation comprising amain vessel and a branch vessel, the method comprising: (i) introducinga bifurcated balloon and stent assembly into the main branch, thebifurcated balloon comprising at least one inflatable portion; (ii)positioning the assembly at the bifurcation; (iii) inflating thebifurcated balloon thereby expanding the inflatable portion and thestent toward the branch vessel.

According to a further aspect, the present invention provides a ballooncatheter, comprising: a catheter having a distal end, a proximal end andan inflation lumen; a balloon formed on the distal end of the catheter,the balloon being in fluid communication with the inflation lumen andbeing capable of being expanded from an unexpanded configuration to anexpanded configuration, wherein the balloon has a herniation in theexpanded configuration.

According to still another aspect, the present invention provides aherniated balloon catheter, comprising: a balloon constructed from acomposite material and including a woven material formed with aherniation, wherein the balloon has a herniation in the expandedcondition.

According to a further aspect, the present invention provides a stentdelivery system, comprising: a catheter having a balloon with aherniation; and a stent having an opening including an outwardlyexpandable portion, the stent being disposed on the balloon with thestent opening aligned with the herniation, whereby upon expansion of theballoon the herniation expands causing the outwardly expandable portionof the stent to extend toward the branch vessel.

According to another aspect, the present invention provides a method fortreating a bifurcated vessel, the method comprising: introducing into avessel a catheter having a distal end, a proximal end, and a guide wirelumen that is adapted to receive a guide wire, a balloon having a distalend and a proximal end, the balloon being disposed near the distal endof the catheter, the balloon having a protrusion at a location betweenthe distal end and proximal end of the balloon, and a stent having aside opening through a wall thereof, the stent being disposed over theballoon, wherein the protrusion of the balloon is positioned through theside opening; positioning the catheter at a bifurcation by aligning theprotrusion with a side branch vessel; and expanding the balloon so as toexpand the stent such that the side opening is aligned with the openingof the bifurcated vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, withreference to the accompanying drawings. With specific reference now tothe drawings in detail, it is stressed that the particulars shown are byway of example and for purposes of illustrative discussion of thepreferred embodiments of the present invention only, and are presentedto provide what is believed to be the most useful and readily understooddescription of the principles and conceptual aspects of the invention.

FIG. 1 is a side view of an illustrative embodiment of a stent deliverysystem constructed in accordance with the present invention.

FIG. 2 is an enlarged side view taken of the distal portion of thesystem of FIG. 1.

FIG. 3 is a view of the stent delivery system of FIG. 1 in a bloodvessel shown approaching a bifurcation in the vessel without a stentmounted thereon in accordance with a method of the present invention.

FIG. 4 is a view of the system of FIG. 3, including a stent mountedthereon.

FIG. 5 is a view of the stent delivery system of FIG. 1 in a bloodvessel located at a bifurcation in the vessel without a stent mountedthereon in accordance with a method of the present invention.

FIG. 6 is a cross-sectional side view of the stent delivery system ofFIG. 1 with a stent mounted thereon and shown in the expanded condition.

FIG. 7 is a perspective view of a balloon configured according to oneembodiment of the present invention.

FIG. 8 is a perspective view of a balloon constructed according to analternative embodiment of the present invention.

FIG. 9 is a perspective view of a balloon configured according to afurther embodiment of the present invention.

FIG. 10 is a perspective view of a balloon configured according to yetanother alternative embodiment of the present invention.

FIG. 11 is a perspective view of a balloon configured according toanother embodiment of the present invention.

FIG. 12 is a perspective view of a balloon catheter configured accordingto another embodiment of the present invention.

FIG. 13 is a perspective view of a portion of a balloon constructedaccording to the principles of the embodiment of FIG. 11.

FIG. 14 is a perspective view of a portion of a balloon constructedaccording to an alternative embodiment of the present invention.

FIG. 15 is a side view of the balloon of FIG. 13 shown in an unexpandedstate.

FIG. 16 is a cross-sectional view of an alternative embodiment of aballoon in an expanded state constructed according the principles of thepresent invention.

FIG. 17 is a cross-sectional view of an alternative embodiment of aballoon constructed in accordance with the present invention.

FIG. 18 is a cross-sectional view of yet another alternative embodimentof a balloon constructed in accordance with the present invention.

FIG. 19 is a cross-sectional view of yet another alternative embodimentof a balloon constructed in accordance with the present invention.

FIG. 20 is a cross-sectional view of still another embodiment of analternative balloon construction formed according to the principles ofthe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to balloon catheters such as balloonangioplasty catheters to treat occlusions in blood vessels. The ballooncatheters can be used alone or with a stent, prosthesis or graft. Such astent delivery system can be used for placement of a stent in a bodylumen, particularly at vessel bifurcations. A preferred stent to bedelivered is generally configured to at least partially cover a portionof a branch vessel as well as a main vessel. In general, a wide varietyof stents and deployment methods may be used with the stent deliverysystem embodiments of the present invention and the present inventionshould be understood to not be limited to any particular stent design orconfiguration. Examples of the types of stents that may be used with thedelivery systems of the present invention are disclosed, for example, inU.S. Pat. No. 6,210,429 to Vardi et al., U.S. Pat. No. 6,325,826 toVardi et al., and co-pending U.S. patent application Ser. No.10/644,550, entitled “Stent With a Protruding Branch Portion ForBifurcated Vessels,” the entire contents of which are incorporatedherein by reference. In general, the aforementioned stent includes abranch portion located at some point along the length of the stent thatis configured to be extendible into a branch vessel in a vesselbifurcation. Once the stent is in position in the main vessel and thebranch portion is aligned with the side branch vessel the stent can beexpanded and the delivery system is particularly adapted to expand thestent branch portion into the side branch vessel. The stent, includingthe branch portion, may be expanded with a single expansion or multipleexpansions.

An illustrative view of one embodiment of a stent delivery system 10constructed in accordance with the present invention is shown in FIG. 1.Stent delivery system 10 generally comprises an elongate main cathetershaft 12 extending from a proximal end 14 to a distal end 16. As bestseen in FIG. 2, distal end 16 has a bifurcated tip structure with twobranch portions, a main vessel branch portion 18 and a side branchsheath 20 that branch off of main catheter shaft 12. A bifurcatedballoon 26 is attached to main vessel branch portion 18 adjacent thedistal end 16 and comprises first and second branch portions 27, 30.First branch portion 27 of balloon 26 comprises an elongate inflatableportion 28. Second branch portion 30 of balloon 26 comprises a secondinflatable portion or auxiliary inflatable portion 32. Second branchportion 30 includes an inflation lumen that branches off from firstbranch portion 27 proximally from the balloon 26 and extendssubstantially adjacent elongate inflatable portion 28. The distal end ofsecond branch portion 30 is attached to first branch portion 27 at alocation distally from the balloon 26. In one preferred embodiment, thedistal end of branch portion 30 is fixedly attached distally of balloon26 in order to prevent at least the second inflatable portion 32 frommoving around the first branch portion 27, although in alternateembodiments it may be removably attached.

In a preferred embodiment, first inflatable portion 28 is generallycylindrical and extends coaxially along main vessel branch portion 18.Second inflatable portion 32 may have a shape and size adapted to extendinto the branch vessel as shown and described herein. For example,portion 32 may have a generally offset configuration and may bepositioned adjacent or in abutting relation with respect to elongateinflatable portion 28.

The first and second inflatable portions can have varied shapes, sizesand positioning in accordance with the principles of the invention. Forexample, in alternative design variations, accurate sizing andpositioning of the inflatable portions relative to the vessel may beachieved.

According to the present invention, the inflatable portions, orballoons, can be constructed of any suitable material. For example, theballoons may be constructed of an appropriate polymeric material.Particular examples include the polyamide family, or the polyamide blendfamily, polyethylene (PE), polyethylene terephthalate (PET),polyurethanes, polyamides, and polyamide blends such as PBAX. Thecompliance of the first inflatable portion 28 and the second inflatableportion 32 can be the same or different. In one preferred embodiment,second inflatable portion 32 is longitudinally positioned at a generallycentral location relative to the first inflatable portion 28. Inalternate embodiments, second inflatable portion 32 may be positioned atany position adjacent first inflatable portion 28.

In a preferred embodiment, balloon branch portions 27 and 30 have acommon inflation lumen 34. Inflation lumen 34 can be conventional, andextend from a portion of the stent delivery system which always remainsoutside of the patient (not pictured). Inflation lumen 34 extendsdistally into each of first and second branch portions 27 and 30 andthus, inflation lumen 34 is in fluid communication with the interiors offirst inflatable portion 28 and second inflatable portion 32. Thusinflation lumen 34 is used to supply pressurized inflation fluid tofirst inflatable portion 28 and second inflatable portion 32 when it isdesired to inflate balloon 26. Inflation lumen 34 is also used to draininflation fluid from first inflatable portion 28 and second inflatableportion 32 when it is desired to deflate the balloon. First and secondinflatable portions are initially deflated when directing the stentdelivery device to the bifurcation lesion in a patient. In thisembodiment, the inflation lumen 34 inflates inflatable portions 28, 32substantially simultaneously. In an alternative embodiment, branchballoon portions 27 and 30 have separate inflation lumens. In thisalternative embodiment inflatable portions 28 and 32 can be inflatedsimultaneously or sequentially. When sequential inflation is desired,preferably, the first inflatable portion 28 is inflated first, followedby the inflation of the second portion 32.

First main guidewire lumen 22 extends through main vessel branch portion18 and first inflatable portion 28. Although first guidewire lumen 22extends through first inflatable portion 28 in the embodiment depictedin FIGS. 1-2, it is distinct from inflation lumen 34 and is not in fluidcommunication with the interior of balloon 26 as shown. Preferably, thefirst guidewire lumen 22 extends distally of first inflatable portion 28and has an open distal end. Alternatively, guidewire lumen 22 can extendthrough branch portion 30.

In the embodiment depicted in FIGS. 1-2, an optional side sheath 20 isillustrated which does not include an inflatable balloon. Although inalternate embodiments side sheath 20 could include an inflatableportion, as described for example in co-pending U.S. patent applicationSer. No. 10/644,550 entitled “Stent With a Protruding Branch Portion ForBifurcated Vessels”. Side sheath 20 is exterior to and distinct frominflation lumen 34 and thus is also not in fluid communication with theinterior of balloon 26 as shown. As shown in the embodiment of FIGS.1-2, side sheath 20 preferably extends distally of balloon 26, and mayinclude a proximal open end 37 at any point along the length of thestent delivery system and a distal open end 39. Side sheath 20 can be ofthe type as described in U.S. Pat. No. 6,325,826 to Vardi, et al., forexample, and in operation the side sheath 20 can extend through a branchaccess hole of the stent.

With reference to FIGS. 3-6, an exemplary manner of practicing theinvention will now be discussed. Referring to FIGS. 3 and 5, thedelivery system is shown in relation to an exemplary body lumen adjacenta blood vessel bifurcation 40 usually comprised of plaque and thedelivery system 10 is shown without a stent mounted thereon (FIGS. 3 and5). FIGS. 4 and 6 show the stent delivery system 10 with a stent 50mounted thereon.

Bifurcation 40 includes a main vessel 42 and a branch vessel 44.Illustrative obstructions 46 located within bifurcation 40 may span orat least partially obstruct main vessel 42 and a proximal portion branchvessel 44. Generally, stent delivery system 10 may be threaded over afirst main guidewire placed in the main vessel to guide the deliverysystem to the treatment site. More specifically, the proximal end offirst guidewire 36 is threaded into the distal open end of the mainguidewire lumen 22 and the delivery system is tracked to a position ator near bifurcation 40, as depicted in FIG. 3. Second guidewire 38 (FIG.5) is then threaded into stent delivery system 10 from the proximal endof the delivery system. More specifically, second guidewire 38 isthreaded into the open proximal end 37 of side sheath 20, and may extendtherefrom through the open distal end 39 of side sheath 20, as depictedin FIG. 5. Alternatively, second guidewire 38 can be resting dormant onthe inside of the side sheath, and when the system is proximal thebifurcation 40, it can be advanced out of side sheath 20 into sidebranch vessel 44. The systems in accordance with the principles of theinvention may be used in over-the-wire or rapid exchange systems, whichmay include rapid exchange on either or both of the side sheath or maincatheter. Rapid exchange is described in one exemplary embodiment inUS2003/0181923 to Vardi et al., published Sep. 25, 2003, the entirecontents of which are incorporated herein by reference.

In one embodiment, the stent delivery system 10 is positioned nearbifurcation 40, and with the distal end 16 (FIG. 1) positioned near sidebranch vessel 44 (FIGS. 3-6), second guidewire 38 is advanced into sidebranch vessel 44 from side sheath 20. Then, the first and secondinflatable portions of balloon 26 are positioned adjacent the opening ofside branch vessel 44 such that auxiliary inflatable side portion 32 ofbifurcated balloon 26 is aligned with side branch vessel. In oneexemplary embodiment, alignment may be achieved using markers, asdescribed in U.S. Pat. No. 6,692,483 to Vardi, et al., the entirecontents of which is incorporated herein by reference. Second guidewire38 remains in side branch sheath 20, and the distal end 16 of system 10remains in main vessel 42. First guidewire 36 remains within firstguidewire lumen 22, and may be further advanced and positioned in mainbranch vessel 42.

Once the system is properly positioned, pressurized fluid is supplied tofirst and second inflatable portions 28 and 32, respectively, of balloon26 to dilate the body lumen and expand a stent mounted thereon (FIG. 6).Preferably, the inflatable portion 28 expands the main body of the stentand inflatable portion 32 expands the side (opening) and expandablebranch structure of the stent, as discussed in more detail withreference to FIG. 6. After inflatable portions 28 and 32 have beeninflated as described above, balloon 26 is deflated by draining theinflation fluid via inflation lumen 34. This allows the inflatableportions 28 and 32 to collapse in preparation for withdrawal of theassembly from vessel 42.

Referring now to FIGS. 4 and 6, one preferred embodiment is shown withstent delivery system 10 and an exemplary stent 50 mounted on theexterior of distal end 16 of the stent delivery system. Stent 50includes an extendible branch portion 52 configured to extend into abranch vessel as discussed in co-pending U.S. application Ser. No.10/644,550, entitled “Stent with Protruding Branch Portion forBifurcated Vessels”. The second inflatable portion 32 may be configuredand positioned to deploy the outwardly expanding stent elements orbranch portion 52 and may be positioned adjacent to the branch portion52, or into a side branch access opening in the stent. As shown in FIG.6, when first and second inflatable portions 28 and 32 are expanded,they simultaneously or sequentially, depending upon the configuration ofthe inflation lumen, cause the stent 50 to expand in the main vessel 42and the branch portion 52 of stent 50 to be pushed or extended into thebranch vessel 44. Upon inflation of the balloon 26, the secondinflatable portion 32 expands and extends the branch portion 52 towardthe branch vessel to open and support the entrance or ostium of the sidebranch artery. This would occur simultaneously when the balloons share acommon inflation lumen but could be sequentially if separate inflationlumens are used. Although a bifurcated balloon is depicted, as shown,more than two inflatable portions or more than two balloons may beutilized with the present invention.

As illustrated, for example, in FIGS. 5 and 6, the first and secondbranch portions 27 and 30 have a longitudinal axis A. The longitudinalaxies are substantially parallel with each other. The term“substantially parallel” is intended to encompass deviations from apurely parallel relationship which may be caused by flexure of thebranch portions 27 and 30, or other components, experienced duringinsertion, travel, and deployment within a body lumen.

FIG. 7 is an enlarged perspective view of the auxiliary inflatable sideportion 32 of bifurcated balloon 26, which is referred to in theprevious embodiments depicted in FIGS. 1-6. According to thisembodiment, the central portion 33 of the auxiliary inflatable sideportion 32 extends in a generally equidistant manner from thelongitudinal axis A, and at an angle of up to about 90° relative tolongitudinal axis A, but other angles are contemplated. As illustratedin FIG. 7, the auxiliary inflatable side portion 32 can have agenerically spherical central portion 33 which is connected to aproximal shaft 41, as well a distal shaft 43. The components of theauxiliary inflatable side portion 32 may be sized appropriately, as willbe readily apparent to those skilled in the art. The central sphericalportion 33 can be provided with a suitable inflated diameter D. Thediameter D can vary according to various factors known to those skilledin the art. According to a non-limiting, exemplary embodiment, thediameter D can be on the order of a few millimeters. For example, thediameter D is on the order of about 1.5-6.0 mm and, preferably, on theorder of about 3.34-3.36 mm.

FIG. 8 illustrates an alternative auxiliary inflatable side portionconstruction 132. According to this embodiment, the central portion 133of the auxiliary inflatable side portion 132 extends in a generallyequidistant manner from the longitudinal axis A, and at an angle of upto about 90° relative to longitudinal axis A, but other angles arecontemplated. As illustrated in FIG. 8, the balloon 132 comprises agenerally elliptical central portion 133, as well as a proximal shaftportion 141, and distal shaft 143 connected thereto. As with theprevious embodiment, the various components of the balloon 132 may besized as appropriate within appropriate dimensional ranges, asdetermined by those skilled in the art. The elliptical central section133 of the balloon 132 is provided with major and minor diameters, D₁and D₂, respectively, as illustrated in FIG. 7. According tonon-limiting exemplary embodiments, the elliptical central section maybe shaped such that the ratio D₂/D₁ is on the order of about 0.8.According to further exemplary non-limiting embodiments, the majordiameter D₁ is preferably on the order of about 3.65-3.85 mm and canrange from 1.5-6 mm, while the minor diameter D₂ is smaller than D₁ andis preferably on the order of about 2.9-3.1 mm.

FIG.9 illustrates yet a further embodiment of auxiliary inflatable sideportion 232 of bifurcated balloon 26 constructed according to theprinciples of the present invention. According to this embodiment, thecentral portion 232 is offset relative to the longitudinal axis A andpreferably extends toward and/or into the branch vessel 44. The centralportion 232 may extend at an angle of up to about 90° relative tolongitudinal axis A, but other angles are contemplated. As illustratedin FIG. 9, the auxiliary inflatable side portion 232 of balloon 26comprises an offset central bulbous or generally spherical portion 233,with a proximal shaft portion 241 and distal shaft portion 243 connectedthereto via a proximal transition section 241 _(T) and distal transition243 _(T), respectively. As with the previous embodiments, the variouscomponents of the auxiliary inflatable side portion 232 of balloon 26can be sized as appropriate, and as readily determined by those skilledin the art. According to exemplary, non-limiting embodiments, theauxiliary inflatable side portion 232 of balloon 26 can be configuredsuch that the central offset portion 233 is provided with a radius ofcurvature R which is on the order of about .50-3.0 mm.

FIG. 10 illustrates yet another alternative embodiment for an auxiliaryinflatable side portion 332 of bifurcated balloon member 26. Accordingto this embodiment, the central portion 332 is offset relative to thelongitudinal axis A and preferably extends toward and/or into the branchvessel 44 (not shown). The central portion 332 may extend at an angle ofup to about 90° relative to longitudinal axis A, but other angles arecontemplated. As shown in FIG. 10, the auxiliary inflatable side portion332 is configured such that it comprises a generally offset ellipticaland cylindrical central section 333, with proximal shaft portions 341and distal shaft portions 343 connected thereto via proximal transitionsection 341 _(T) and distal transition portion 343 _(T), respectively.The offset central section 333 is preferably configured such that itcomprised a first diameter D₁ and second diameter D₂ wherein D₁ and D₂have different values (D1≠D2). The dimensions of the various constituentcomponents of the auxiliary inflatable side portion 332 can bedetermined by those skilled in the art. According to exemplarynon-limiting embodiments, the auxiliary inflatable side portion 332 canbe configured such that it is provided with first and second diameterssuch that the ratio D₂/D₁ is on the order of about 0.25-4.0 mm.According to further, non-limiting examples, the auxiliary inflatableside portion 332 can be configured such that it is provided with a firstdiameter D₁ which has dimensions on the order of about 1.5-6.0 mm and,preferably about 2.7-2.9 mm, and a second diameter D₂ which hasdimensions on the order of about 1.5-6.0 mm, and preferably about2.1-2.3 mm.

FIG. 11 illustrates yet another alternative embodiment of an auxiliaryinflatable side portion 432 of bifurcated balloon 26. According to thisembodiment, the central portion 432 is offset relative to thelongitudinal axis A and preferably extends toward and/or into the branchvessel 44 (not shown). The central portion 432 may extend at an angle ofup to about 90° relative to longitudinal axis A, but other angles arecontemplated. The auxiliary inflatable side portion 432 is configuredsuch that it comprises an offset generally cylindrical central section433 having a proximal shaft portion 441 and a distal shaft portion 443connected thereto via proximal transition shaft portion 441 _(T) anddistal transition portion 443 _(T), respectively. The variousconstituent components of the balloon 432 can be configured withrelative dimensions which can be ascertained by those skilled in theart. According to exemplary, non-limiting examples, the balloon 432 canbe configured such that it is provided with an offset generallycylindrical central section 433 having a diameter D which is on theorder of about 1.5-6.0 mm.

FIGS. 12-15 illustrate further alternative embodiments of the presentinvention which can be utilized in the treatment of branch arteries,including incorporation into stent-delivery systems of the typepreviously described. The balloons depicted in the embodiments of FIGS.12-15 can be referred to as “herniated” balloon configurations thatfunction in a manner similar to the embodiments described above. Theherniated balloon configuration is characterized by having a generallycylindrical shape in an unexpanded configuration, and a generallycylindrical shape with a generally hemispherical appendage that inflatesoutwardly relative to the longitudinal axis of the balloon toward thebranch artery in an expanded state or configuration. This protrusion canbe referred to as a herniation, bulge, protrusion, or extension. Theparticular shape, size, and configuration of the balloon and theherniations illustrated herein are exemplary, and may be modified fromthat explicitly shown and described. The expandable herniation, bulge,protrusion, or extension can be expandable towards the entrance of sidebranch (e.g. —44, FIG.3) over a suitable dimension, such as 1-4 mm.

The embodiments of the balloons depicted in FIGS. 12-15 can be utilizedin a manner similar to that which has been described in connection withpreviously illustrated embodiments (see, e.g. —FIGS. 1-6).

With regard to the embodiments depicted in FIGS. 12-15, it should beunderstood that the herniated balloon constructions depicted therein canbe utilized as one or more of the first and second inflatable portionsof a bifurcated balloon (e.g. 26, FIGS. 1-6). Alternatively, theherniated balloon constructions can be utilized in place of abifurcated-type balloon. In other words, the herniated balloon can beutilized by itself instead of a balloon construction which relies upondistinct first and second inflatable portions. An exemplary embodimentof a herniated balloon catheter 526 is illustrated in FIG. 12. In theillustrated embodiment, the herniated balloon catheter 526 comprises anelongated inflatable portion 528 and a herniation, bulge, protrusion, orextension 532 therewith. In the embodiment of FIG. 12 the ballooncatheter further includes a lumen 534 which can serve to communicatepressure for inflation of the balloon catheter 526, and provide apassage way for a guide wire, etc.

The particular configuration and dimensions of the balloon catheter 526can vary according to a number of factors. For purposes of illustrationonly, certain suitable, but non-limiting, dimensions of variouscomponents of the balloon catheter 526 will now be described. Theballoon catheter 526 can be provided with a length dimension L₁ which isabout 4-100 mm. The balloon can be provided with an outside diameterOD₁, which is on the order of about 1-10 mm, and the herniation 532 canbe provided with a radius of curvature R₁ which is about 0.5-3 mm.

FIG. 13 illustrates a portion 526′ of a herniated balloon catheter,which includes a herniation 533′. According to further non-limitingexamples, the balloon portion 526′ can be provided with the followingsuitable dimensions: outside diameter OD₂ of 1-10 mm; a length dimensionL₂ of about 4-100 mm; a wall thickness dimension T₂ of about 0.003-0.005mm and a radius of curvature R₂ of the herniated portion 533′ of about0.05-3 mm.

Another alternative herniated balloon construction is shown in FIG. 14,where the herniated balloon portion 526″ is provided with analternatively configured herniation 533″. Illustrative and non-limitingexamples of suitable dimensions according to this embodiment include: anoutside diameter OD₃ (FIG. 15) of about 1-10 mm; a length dimension L₃of about 4-100 mm; a height dimensions H of the herniation 533″ of about1-6 mm; and a radius of curvature R₃ of the herniation 533″ of about0.5-3 mm; and a wall thickness of the herniated balloon catheter portion526″ of about 0.01 mm.

Although the herniation 533, 533′, and 533″ of the embodimentsillustrated in FIGS. 12-15 are shown as being centrally located on theherniated balloon catheter 526 or herniated balloon catheter portions526′, 526″, it should be noted that the herniation 533, 533′, and/or533″ maybe located at any desired position along the length of theballoon. For example, once associated with a stent, it can preferably beplaced such that it corresponds to the location along the middle ⅓of thestent.

The balloon 526, 526′, and/or 526″ can be constructed of any suitablematerial such as those previously disclosed herein. In addition, theballoon 526, 526′, and/or 526″ can be constructed of a compositematerial. Suitable materials include a combination of elastomeric andsemi to non-compliant materials such as: urethane; silicone; nylon;latex; (elastomeric) polyethylene hytrel pebax polyaryletherthketone;polyoxymethylene; polyamide; polyester thermoplasticpolyetheretherkatone; and polypropylene (semi non-compliant). Theballoon 526, 526′, and/or 526″ can be also be constructed by combiningthe above-disclosed materials with woven textile materials such asKevlar, silk, cotton, wool, etc. This can be accomplished by winding orweaving a textile material onto a rod that has the shape of the desiredherniated balloon. The polymer component of the composite is thenextruded or dip-coated over the rod. This composite structure is thencured, heat set, or adhesively fused together. The rod is then removedand the remaining shape comprises the herniated balloon 526, 526′,and/or 526″.

The herniation 533, 533′, and/or 533″ can be provided by adding anappendage to a conventional balloon by using a molded collar oradhesively attaching an object to the surface of the balloon, or byusing a mound of adhesive to create the herniation.

The balloon 526, 526′, and/or 526″ can be constructed by molding threesmall balloons and attaching them in tandem. The central ballooncomprising the desired shape of the herniation. These balloons wouldshare a common inflation port. When the balloons are inflated, thecenter balloon expands in the desired manner to form the herniation.

According to further aspects of the present invention, more than twoinflatable portions or more than two balloons may be utilized. Forexample, as shown in FIGS. 16-18, the balloon may include a plurality ofsecond inflatable portions. In this regard, a user may be able to treatmultiple bifurcations with a single device. Such a configuration, mayalso eliminate the need for a secondary positioning lumen (side sheath20) and reduce the profile of the system. As shown in FIGS. 16-17, inone exemplary embodiment, balloon 626 includes four inflatable portions662 positioned radially around a first inflatable portion 660. In analternate embodiment, shown in FIG. 18, a plurality of inflatableballoon portions 662 are spaced longitudinally adjacent one side offirst inflatable portion 660.

Referring to FIG. 19, a cross-sectional view of an alternativeembodiment of a balloon 772 is shown. Balloon 772 includes a maininflatable portion 774 and further extends into secondary inflatableportion 776. Lumen 778 can be of various diameters, compliances, andmaterials to control the timing and size of the secondary expandableportion 776 upon inflation. In one embodiment, second expandable portion776 may deploy subsequent to main expandable portion 774. Such a timedelay may be achieved, for example, using a smaller diameter inflationlumen leading up to secondary expandable portion 776 since the inflationfluid travels along path 779 first through the main expandable portion774 and then on to secondary expandable portion 776. In this regard,delivery system 770, may permit sequential deployment of two expandableportions using a single inflation port.

Referring to FIG. 20, a cross-sectional view of an alternativeembodiment of a balloon 880 is shown in an expanded state. Balloon 880comprises a main inflatable portion 882 and an auxiliary inflatableportion 884. Main expandable portion 882 has an indentation or cavityconfigured and dimensioned to received a portion of auxiliary expandableportion 884 when balloon 880 is inflated. For example, as shown in FIG.20 auxiliary inflatable portion is generally spherically shaped and wheninflated, cavity 886 is aligned and positioned to accommodate a portionof the spherical shape. In this regard, when balloon 880 is inflated,the inflated balloon has the approximate peripheral shape of a cylinderwith a hemispherical protrusion. In use, the auxiliary expandableportion 884 is configured to deploy or extend outwardly deployableelements of a stent into a bifurcation. In operation, when bothexpandable portions are inflated, such a balloon configuration allowsfor varying expansion capabilities and preferably prevents the region ofa stent adjacent second inflatable portion 884 from over expanding intothe bifurcated region. As a result, the possibility of causing trauma tothe vessel is preferably limited.

While the invention has been described in conjunction with specificembodiments and examples thereof, it is evident that many alternatives,modifications and variations will be apparent to those skilled in theart upon reading the present disclosure. Accordingly, it is intended toembrace all such alternatives, modifications and variations that fallwithin the spirit and broad scope of the appended claims. Furthermore,features of each embodiment can be used in whole or in part in otherembodiments.

1. A system for treatment of a bifurcation of a body lumen, thebifurcation comprising a main vessel and a branch vessel, the systemcomprising: a catheter for insertion into said body lumen, the catheterhaving a distal end, a proximal end, and an inflation lumen; a balloonin fluid communication with the inflation lumen, the balloon having afirst branch and a second branch, the first branch including aninflatable portion and the second branch comprising an inflatableportion having a generally bulbous shape adapted to extend toward thebranch vessel upon inflation, the second branch of the balloon having aproximal end attached to the first branch proximal the inflatableportion of the first branch and the second branch having a distal endattached directly to the first branch distal the inflatable portion ofthe first branch; and a stent disposed on the balloon, the stent havingan opening including an outwardly expandable portion, the openingaligned with the inflatable portion, whereby expansion of the inflatableportion causes the outwardly expandable portion to extend toward thebranch vessel.
 2. The system of claim 1, wherein the first branch andthe second branch each have a longitudinal axis, the longitudinal axisof the first branch portion being substantially parallel to thelongitudinal axis of the second branch portion.
 3. The system of claim1, wherein the inflatable portion of the second branch is generally inthe form of an elliptical cylinder.
 4. The system of claim 1, whereinthe inflatable portion of the second branch is generally in the form ofan offset cylinder.
 5. The system of claim 1, wherein the inflatableportion of the second branch is generally in the form of an offsetbulbous portion.
 6. The system of claim 1, wherein the second branchportion comprises a plurality of inflatable portions.
 7. The system ofclaim 6, wherein the inflatable portions are arranged relative to eachother along a longitudinal axis of the second branch of the balloon. 8.The system of claim 1, wherein the catheter further comprises a secondguidewire lumen external to both the first branch and the second branchof the balloon, the second guidewire lumen configured to extend into thebranch vessel.
 9. The system of claim 1, wherein the first branch of theballoon extends coaxially along a first guidewire lumen.
 10. The systemof claim 1, wherein the first branch of the balloon defines anindentation configured to receive a portion of the inflatable portion ofthe second branch of the balloon.
 11. A system for treatment of abifurcation of a body lumen, the bifurcation comprising a main vesseland a branch vessel, the system comprising: a catheter for insertioninto said body lumen, the catheter having a proximal end portion and adistal end portion, the distal end portion defining a first branch and asecond branch, each of the first and second branches defining aninflation lumen, the second branch having a proximal end and a distalend, each of the proximal and distal ends of the second branch beingfixedly coupled to the first branch; a first balloon arranged on thefirst branch between the proximal and distal ends of the second branch,the first balloon being arranged in fluid communication with theinflation lumen of the first branch; a second balloon arranged on thesecond branch in fluid communication with the inflation lumen of thesecond branch, the second balloon including an inflatable portion havinga generally bulbous shape adapted to extend toward the branch vesselupon inflation; and a stent disposed about the first balloon and thesecond balloon.
 12. The system of claim 11, wherein the stent defines anopening and includes an outwardly expandable portion arranged adjacentthe opening, the outwardly expandable portion being aligned with theinflatable portion of the second balloon, whereby expansion of theinflatable portion of the second balloon causes the outwardly expandableportion to extend toward the branch vessel.
 13. The system of claim 11,wherein the catheter further comprises a second guidewire lumen externalto both the first branch and the second branch of the balloon, thesecond guidewire lumen configured to extend into the branch vessel. 14.The system of claim 11, wherein the second balloon is configured toinflate simultaneously with inflation of the first balloon.
 15. Thesystem of claim 11, wherein the inflatable portion of the second balloonis generally in the form of an offset cylinder.
 16. The system of claim11, wherein the first branch and the second branch each have alongitudinal axis, the longitudinal axis of the first branch beingsubstantially parallel to the longitudinal axis of the second branch.17. The system of claim 11, wherein the inflation lumen of the secondbranch splits from the inflation lumen of the first branch proximal thefirst balloon.
 18. The system of claim 11, wherein the inflation lumenof the second branch is coupled in fluid communication to the firstbranch distal the first balloon.
 19. A system for treatment of abifurcation of a body lumen, the bifurcation comprising a main vesseland a branch vessel, the system comprising: a catheter for insertioninto said body lumen, the catheter having a distal end portion, aproximal end portion, and an inflation lumen; a balloon extending fromthe distal end portion of the catheter in fluid communication with theinflation lumen, the balloon having a first branch and a second branch,each of the first and second branches having a longitudinal axis, thelongitudinal axis of the first branch being substantially parallel tothe longitudinal axis of the second branch, the first branch includingan inflatable portion arranged coaxial with the longitudinal axis of thefirst branch, the second branch being fixedly attached to the firstbranch proximal and distal the inflatable portion of the first branch,and the second branch including at least a first inflatable portionbeing generally cylindrical and arranged offset from the longitudinalaxis of the second branch; and a stent disposed on the balloon, thestent having an opening including an outwardly expandable portion, theopening aligned with the first inflatable portion of the second branch,whereby expansion of the first inflatable portion causes the outwardlyexpandable portion to extend toward the branch vessel.
 20. The system ofclaim 19, wherein the second branch includes a plurality of inflatableportions spaced longitudinally along the second branch.